Illuminated oil-tight pushbutton



Dec. 8, 1959 'r. l. MASLlN ETAL 2,916,673

ILLUMINATED OIL-TIGHT PUSHBUTTON Filed July 9, 1957 INVENTORS THOMAS I.MAsuN, ORVAL A. HERMAN ATTORNEY United States PatentO 2,916,673IL'LUMINATED OIL-TIGHT PUSHBU'ITON Application July 9, 1951, Serial No.670,682

' 4 Claims. 01. 317-99 j invention relates to an illuminated pushbuttonapparatus for panel mounting and more particularly to industi ialilluminated assemblies and switch units having provision for preventingthe leakage of oil through the pushbutton'a'ssembly or its mounting.

, In-'a co-pending application Serial No. 670,681, filed Jiily'9; 1957,and assigned to the same assignee as the present application, anilluminated oil-tight pushbutton switch unit is disclosed in which alamp is fixedly mounted on a" transformer fastened to the rear of thepushbutton assembly and the lamp extends within a hollow reciprocatinglight-transmitting pushbutton actuating. member. The present inventionis an improvement over the pushbutton assembly disclosed in thisco-pending patent application Serial No. 670,681.

' While the pushbutton apparatus disclosed in this copending applicationsolved many of the major problems involved in prior type illuminatedpushbuttons, it was found that several inconveniences and troubles stillremained in the use of the disclosed apparatus. For example, since oneof the oil seals for the reciprocating portion of the pushbutton waslocated below the operating spring, it'was found possible for dirt andoil to accumulate around the spring and impede its proper functioning.Since the pushbutton assembly was formed in two parts screwed'together,it was possible for repeated operation ofthe button to loosen theconnection and permit oil leakage." The pushbutton assembly alsoextended an undesirably great distance beyond the panel to which it wasmounted whereby the' light-transmitting end of the pushbutton could beeasily struck and broken. Moreover, it was found that the use ofcommercially available transformers made the entire apparatus ratherunwieldly and bulky.

Accordingly, one of the objects of the present invention is to providean illuminated oil-tight pushbutton assembly and switch unit of smallerover-all size in which the lamp ,maybe easily replaced and in which theoil seals are locatedso that they remain tight during operation andprevent dirt and oil from reaching the interior of the pushbuttonassembly or its operating spring.

'Another object of the invention isto provide a transformer constructionfor an illuminated pushbutton apparatus or switch unit which may bemounted closely alongside an electric switch and interchanged orreplaced by a similar switch.

A further object of the invention is to provide illuminated oil-tightpushbutton apparatus which may be easily modified to include a shield orguard around the projecting light-transmitting end of the pushbuttonactuating member.

In general, in accord with the invention both the stationary andwipingseals of the pushbutton assembly itself are located close to the forwardend of the pushbutton assemblythereby permitting the portion of thepushbutton assembly beyond the front panel to be foreshortened andsimultaneously. protecting all of the moving parts of the pushbuttonincluding the operating spring from exposure to dirt or oil leakage. Thewipe seal is carried by an annular guide member which surrounds the sidewall of the cylindrical light-transmitting pushbutton actuating memberand serves also to guide that member in its reciprocating motion whilebeing removable from the base of the pushbutton assembly to permitaccess to the internal lamp without disturbing the mounting of thepushbutton assembly upon its supporting panel.

-In accord with a further feature'of the invention, an electric switchand a transformer are mounted alongside one another on the rear of thepushbutton assembly and the transformer is constructed to have the samesize and rectangular configuration as the electric switch so as to beinterchangeable with the switch, forming together with the switch agenerally rectangular block whose crosssectional area is approximatelythe same as that of the pushbutton assembly to which it is mounted. Inthis way a self-contained illuminated pushbutton switch unit is providedhaving an unusually small size and compact arrangement.

In a modification of the invention the annular guide member surroundingthe upper portion of the light-transmitting pushbutton is alsoconstructed to serve as a lighttransmitting guard against accidentaloperation of the pushbutton or breakage of the projecting pushbuttonend.

The novel features believed characteristic of the invention are setforth in the appended claims. The invention itself, however, togetherwith further objects and advantages thereof, may be easily understood byreferring to the following description taken in connection with theaccompanying drawing in which:

Figure v1 is a side elevation view of pushbutton apparatus or switchunit embodying one form of the invention;

Figure 2 is a similar view showing the details of the pushbuttonapparatus in cross-section;

Figure 2A is a detail view of the lamp and lamp socket of the apparatusof Figure l;

Figure-3 is an exploded perspective view of the pushbutton apparatus ofFigure 1, and

Figure 4 is a side elevation view of a pushbutton guard member which maybe used in connection with the apparatus of Figure 1.

Referring to Figure 1, the invention is shown in one form as comprisingan illuminated pushbutton apparatus 10 including a pushbutton assembly11 to the rear of which is attached an electric switch 12 and atransformer 13. A mounting base or plate 14 at the rear of pushbuttonassembly 11 serves to hold these three components in assembled relationto one another. Alternatively, plate 14 may be fastened to the rear ofswitch 12 and transformer 13 and then assembled to the rear surface ofan enclosure with the front cover being used to support and positionassembly 11 for proper operation of switch 12. The pushbutton apparatus10 when in use is mounted on a panel 15 in a manner to be described.

As shown in Figures 2 and '3, switch 12 is of the type described in U.S.Patent 2,712,580 with a. rectangular housing 16 and a depressibleoperating member 17 extending through the top of housing 16. Switch 12has two pairs of terminals 18, 19 extending from opposite sides thereof,the upper terminals being normally bridged when the operating member 17is elevated and the lower pair of terminals 19 being bridged when theoperating member 17 is depressed.

Transformer 13 is preferably also rectangular, as shown, with a pair ofprimary winding terminals 20 extending from opposite sides thereof and apair of secondary winding leads 21 extending through the top thereof.The laminations and coils of transformer 13 are preferably embedded inany suitable insulating molded plastic compound such as one kind now generally known as Permafil. Transformer 13 also carries a lamp socket 22and a lamp 23 on a bracket 24 fastened to the top of transformer 13.Lamp 23 is preferably of the pin base type which merely plugs into apin-receiving socket 22, as shown in Figure 2A. Bracket 24 also providesa shock type mounting for lamp socket 22 thereby reducing breakage oflamps due to vibration. The secondary winding leads 21 are fastened tothe terminals 25 of lamp socket 22. Switch 12 and transformer 13 haveapproximately the same width, each approximately one-half the diameterof the base of the pushbutton assembly 11 to which they are fastened.Switch 12 and transformer 13 thus form a rectangular lock whosecross-sectional area is approximately the same as that of the base ofthe pushbutton assembly 11.

Pushbutton assembly 11 is hollow and open at the bottom and the lampassembly 22, 23 and the switch operating member 17 extend Within theinterior of the switch assembly 11 through its open bottom.

The principal components of the pushbutton assembly comprise acylindrical pushbutton base member 30, clamping means for fastening theassembly to the supporting panel 15, a slidable two-part pushbuttonactuating member 31, 56, the outer part 31 being of lighttransmittingconstruction and means for guiding the reciprocating movement ofactuating members 31, 56 and for sealing the assembly against oilleakage. Base member comprises a hollow cylindrical base portion 33 andan upper reduced diameter neck portion 34 threaded on both the inner andouter cylindrical surfaces of its upper end. Four rectangular recesses36 angularly displaced 90 from one another are formed in the outercylindrical surface of neck portion 34 traversing the outer threadsthereof. These recesses aid in the prevention of rotation of thepushbutton assembly when it is fastened down to its supporting panel 15in a manner to be explained.

The means for fastening the pushbutton assembly 11 to panel 15 comprisesa plurality of washers 38, a resilient sealing ring or gasket 39, aretaining or positioning ring 40, and an annular threaded fastening ringor clamping collar 41. Washers 38 and sealing ring 39 are locatedbeneath panel 15 between the panel and a shoulder 42 of base member 30.Retaining ring is located immediately above panel 15 and hasdiametrically opposed ears 43, 44 extending inwardly a short distance.Ear 43 fits within one of the recesses 36 on the upper end of casemember 30. Bar 44, however, is bent downwardly and fits within a keyslot 45 extending outwardly from the circumference of an aperture 46 inpanel 15 through which the pushbutton assembly is inserted during themounting operation. Tightening of fastening collar 41 down upon theexternal threads 35 of base member 30 clamps the washers 38, sealingring 39 and retaining ring 40 together on opposite sides of thesupporting panel 15 thereby sealably to mount the assembly and lock itagainst rotation thereafter.

Light-transmitting portion 31 of the two part pushbutton actuatingmember is a hollow cup-shaped cylindrical member open at the bottom andclosed at the top. Lamp assembly 22 and 23 extends within the openbottomof this light-transmitting actuating member 31 with the upper endof lamp 23 spaced from the front end 48 of the actuating member 31.Member 31 is supported for sliding reciprocating motion by cylindricalguiding collar 32 threaded to the internal surface of the cylindricalneck portion 34 of base member 30. Annular guide collar 32 carries aresilient wiping seal 50 embedded adjacent its upper end so as to wipeagainst the outer cylindrical wall of pushbutton actuating member 31.Guide collar 32 also carries a stationary resilient seal or gasket 51around its lower threaded portion 52. By threading guide member 32 downinto base member 30. the sealing ring 51 is clamped between the upperend of base member 30 and the shoulder 53 of the guide member 32 therebyto tightly seal the two inter-connected parts against oil leakagetherethrough.

As best seen in Figure 2, the lower end portion 55 of thelight-transmitting portion 31 of the pushbutton actuating member engagesand fits within a cylindrical actuating sleeve 56 which moves togetherwith pushbutton member 31 to engage and depress or disengage and releasethe operating member 17 of switch 12. The actuating sleeve 56 isslidably positioned within the pushbutton base member 30. A conical,helical spring 57 is trapped between a ridge 58 on actuating sleeve 56and a lip 59 fastened to the bottom of collar of base member 30 andserves to bias the actuating sleeve 56 and light-transmitting actuatingmember 31 toward their normal elevated or outer positions. The outerdiameter of actuating sleeve 56 is such as to form a loose fit Withinthe hollow cylindrical base member 30. It will be noted that operatingmember 17 of switch 12 is located: immediately beneath the lower rim ofactuating sleeve 56 for engagement thereby and that the internal surfaceof the base portion 33 of base member 30 is conically tapered outwardlytoward the bottom to accommodate the switch operating member 17. Thelight-transmitting actuator 31 is limited in its outward movement beyondits desired elevated position by an outer ridge 60 formed around thelower portion thereof which hits against an annular shoulder or ridge 61formed in the lower inner surface of guide collar 32. In addition,outward movement of the actuating sleeve 56 is limited by an internalannular stop shoulder at the upper end of the pushbutton base member 30(Fig. 2), whereby the guide collar 32 and the light-transmittingactuating member 31 may be removed as a unit without displacement of theactuating sleeve 56.

By this construction a burned out lamp 23 may be easily replaced bymerely unscrewing guide collar 32 and then lifting the pushbuttonactuating member 31 out of the base member 30 thereby exposing the lampfor replacement. The lamp may be quickly and easily inserted by a simpleplug-in motion. It will be observed that the seal 50 wipes against thenormally exposed cylindrical walls of the lighttransmitting member 31during operation of the pushbutton thereby tending to keep these wallsclean since this seal 50 is located at the upper end of guide member 32.It will further be observed that all of the operating and moving partsof the pushbutton switch are located internal of the switch beyond theoil seals so that they remain free of dirt or oil. A further feature ofthe construction is that the secondary leads from the transformer arelocated entirely within the base member 30 of the pushbutton assemblyand are therefore protected thereby.

Referring now to Figure 4, there is shown a guarding guide member orguard 65 which may be used in substitution for the guide member 32 whereit is desired to protect the exposed end of the light-transmitting,pushbutton member 31. Guard 65 is identical to the guide member 32 withthe exception that it contains a cylindrical shielding portion 66 whichsurrounds the upper end of pushbutton member 31 in spaced relationthereto. Shielding portion 66 has apertures 67 formed therein forpermitting the passage of light therethrough and also for permitting theescape of oil, dirt and chips. Guard 65 carries the internal wipe seal50 and the external stationary seal 51 in the same manner as guidemember 32 described above.

Although we have described our invention in connection with a specificconstruction, many modifications, may

be made. We intend, therefore, by the appended claims to cover all suchmodifications as fall within the true spirit and scope of the invention.

What we claim as new and desire to secure by Letters- Patent of theUnited States is:

1. An oil tight illuminated pushbutton switch unit com-. I prising anelectric switch having a movable operating member extending therefrom, ahollow cylindrical pushbutton base member mounted upon said switch withsaid operating member extending into the bottom of said hollow basemember, said base member having an upper portion threaded internally, anannular guiding collar threaded internally into said uper base portionand having an internal guiding surface including a resilient sealingring, a hollow cylindrical light transmitting pushbutton actuatingmember reciprocably mounted in said guiding collar in sliding engagementwith said sealing ring and extending into said base member to engage andmove said switch operating member, said actuating member having on theend within said base member an external annular stop shoulder engagingsaid guiding collar to limit outward movement of said actuating member,and a lamp socket fixedly mounted within said light transmittingpushbutton actuating member 2. An oil tight illuminated pushbuttonswitch unit comprising an electric switch having a movable operatingmember extending therefrom, a hollow cylindrical pushbutton base membermounted upon said switch with said operating member extending into thebottom of said hollow base member, said base member having an upperportion threaded internally, a cylindrical actuating sleeveconcentrically and slidably mounted in said base member to engage andmove said switch operating member, said internally threaded upperportion of said base member including stop means limiting outwardmovement of said actuating sleeve, spring means in said base memberbiasing said sleeve outwardly against said stop means, an annularguiding collar threaded internally into said upper portion of said basemember and having an internal guiding surface including a resilientsealing ring, a hollow cylindrical light-transmitting pushbuttonactuating member reciprocably mounted in said collar to engage and movesaid actuating sleeve against its bias and having on its inner end anexternal annular stop shoulder engaging said guiding collar to limitoutward movement of said actuating member, and a lamp socket mounted insaid base and extending into said light-transmitting push-buttonactuating member, said pushbutton actuating member and said guidingcollar being removable as a unit to provide access to said lamp socket3. An oil tight illuminated pushbutton switch unit as claimed in claim 2in which said light-transmitting pushbutton actuating member includes anexternal annular shoulder and said guiding collar provides stop meansengaging said shoulder to limit outward movement of said pushbuttonactuating member.

4. An oil tight illuminated pushbutton switch unit for panel mountingcomprising an electric switch having a movable operating memberextending therefrom, a hollow cylindrical pushbutton base member mountedupon said switch with said operating member extending into the bottom ofsaid hollow base member, said base mem her having an upper portion ofreduced cross section forming a first annular shoulder externally ofsaid base member and said upper portion being threaded internally andproviding beneath said threads an internal annular stop shoulder, acylindrical actuating sleeve concentrically and slidably mounted in saidbase member to engage and move said switch operating member, springmeans in said base member biasing said sleeve outwardly against saidinternal stop shoulder, an external clamping collar threadedly mountedexternally upon the upper portion of said base member whereby saidswitch unit may be mounted upon a panel clamped between said firstannular shoulder and said clamping collar, an annular guiding collarthreaded internally into said upper portion of said base member andhaving an internal guiding surface including a resilient sealing ring,the inner end of said guiding collar being formed to provide a thirdannular stop shoulder and the outer end of said guiding collar being ofenlarged cross section to provide externally thereof a fourth annularshoulder, a sealing ring interposed between said fourth shoulder and theupper end of said base member, a hollow cylindrical light-transmittingpushbutton actuating member reciprocably mounted in said guiding collarto engage and move said actuating sleeve against its bias, saidpushbutton actuating member having an external annular shoulder engagingsaid third shoulder to limit outward movement thereof, and a lamp socketmounted in said base and extending intosaid light-transmittingpushbutton actuating member, said pushbutton actuating member and saidguiding collar being removable as a unit to provide access to said lampsocket.

References Cited in the file of this patent UNITED STATES PATENTS2,264,680 Roper Dec. 2, 1941 2,273,353 Harris Feb. 17, 1942 2,428,848Koenig Oct. 14, 1947 2,430,189 Schellman Nov. 4, 1947 2,605,322 EdsallJuly 29, 1952 2,605,849 Bordelon Aug. 5, 1952 2,610,237 Benner Sept. 9,1952 2,666,829 Burkhard Jan. 19, 1954 2,707,213 Koertge Apr. 26, 19552,723,328 Verkuil Nov. 8, 1955

